Isocyanates account for the highest number of reported cases of occupational asthma in the U.S. and developed countries. Prevention, however is limited by inadequate knowledge of isocyanate routes of exposure, exposure patterns, mechanisms of sensitization and other causal factors. A 5-year cross-sectional epidemiologic survey of painters and repairers of autobodies at Yale (SPRAY) was therefore initiated and funded to address these questions. At the outset of Spray, it was not known how frequent skin contact among the painters might be. Moreover, there is new and exciting data from animal studies demonstrating that dermal rather than respiratory contact may be crucial to immune sensitization leading to asthma. Little is known, so far, about dermal exposure in autobody shops and its modifiers, especially the effectiveness of personal protective equipment (PPE) in preventing workers from skin contamination by isocyanates. To address these issues, we propose a dermal exposure assessment study of HDI as an additional ancillary component to SPRAY. Our specific aims are to: 1) Qualitatively and quantitatively assess surface and skin contamination of HDI; 2) Identify modifiers that affect surface and skin contamination, and specifically evaluate the effectiveness of PPE in protecting the skin from isocyanate contamination; 3) Explore the relationships of dermal exposure with airborne exposure, biomarkers of systemic absorption and skin sensitization, and asthma-developing risk. The study will be integrated into the SPRAY. The overall design will be a cross-sectional investigation of 20 shops with 120 workers. This should allow us to better understand the complex basis for asthma risk in these workers, and to make better recommendations to autobody shops and workers on the protective measures of isocyanate dermal exposures.